cos (2x) = cos x
2 cos^2 x -1 = cos x using the double angle formula
2 cos ^2 x -cos x -1 =0
factor
(2 cos x+1) ( cos x -1) = 0
using the zero product property
2 cos x+1 =0 cos x -1 =0
2 cos x = -1 cos x =1
cos x = -1/2 cos x=1
taking the arccos of each side
arccos cos x = arccos (-1/2) arccos cos x = arccos 1
x = 120 degrees x=-120 degrees x=0
remember you get 2 values ( 2nd and 3rd quadrant)
these are the principal values
now we need to add 360
x = 120+ 360n x=-120+ 360n x = 0 + 360n where n is an integer
In this question, you're simplifying the inequality by solving for x.
Solve for x:
12 > -3x + 6
<em>flip the equation:</em>
-3x + 6 < 12
<em>subtract 6 from both sides</em>
-3x < 6
<em>divide both sides by -3, while also flipping the inequality</em>
x > -2
Answer:
x > -2
Answer
-3m + 17
Step-by-step explanation:
A coefficient is a number that goes in front of the variable, so -3 would go in front of m. A constant is just a number on it's own, so it would be +17
Answer:
C6 greeting cards for $23.40
Step-by-step explanation:
A. 13.5/3=4.5
B. 38.25/9=4.25
C. 23.4/6=3.9
d. 32.8/8=4.1
